Loose stools and nausea late in pregnancy often cause anxiety, leading expectant parents to wonder if labor is imminent. While these digestive disturbances are uncomfortable, they can be a natural, though not guaranteed, sign that the body is preparing for childbirth. Understanding the connection between these symptoms and labor, and when they indicate a non-labor issue, is important.
The Physiological Link to Imminent Labor
The body’s preparation for labor involves hormonal changes that often affect the digestive system. Prostaglandin, a primary hormone, surges to soften and prepare the cervix for delivery.
Prostaglandins stimulate smooth muscle tissue throughout the body, including the intestinal tract, leading to increased gut motility. This results in the loose stools or diarrhea some women experience in the hours or days preceding labor. This gastrointestinal effect is an indirect consequence of the hormone’s role in initiating uterine contractions.
Vomiting and nausea can occur as a physical response to hormonal shifts or due to the baby’s position. As the baby descends into the pelvis, the uterus exerts increased pressure on surrounding organs, including the stomach and intestines. This physical crowding can disrupt normal digestion and contribute to nausea.
These digestive symptoms are early signs, but they are not a definitive indicator that active labor is imminent. They may precede contractions by a few hours or a couple of days, and not all women experience this digestive “clean-out” before giving birth.
Ruling Out Non-Labor Related Causes
While a link to impending labor exists, digestive distress in late pregnancy is frequently caused by factors unrelated to childbirth. The most common alternative is acute gastroenteritis, often called a stomach bug, which is typically viral or bacterial. This illness is often accompanied by a fever, body aches, or prolonged symptoms without the onset of rhythmic contractions.
Food poisoning is another non-labor cause that can trigger sudden vomiting and diarrhea. Differentiating this from labor preparation involves looking for the absence of true, patterned uterine contractions that increase in intensity. Labor-related diarrhea or nausea is often brief, occurring as the body clears itself out, while illness can persist for a day or more.
Vomiting in the second half of pregnancy can also signal a serious complication like preeclampsia. This condition is typically accompanied by other symptoms, such as severe headaches not relieved by medication, visual disturbances, or pain just below the ribs. Digestive issues may also stem from dietary changes, increased sensitivity to prenatal vitamins, or pre-existing conditions like Irritable Bowel Syndrome (IBS).
Hydration and Critical Next Steps
Regardless of the cause, the immediate concern when experiencing vomiting and diarrhea in late pregnancy is the risk of dehydration. Losing fluids and electrolytes can affect maternal health and uterine activity, making fluid replacement a priority. Oral rehydration solutions (ORS) are formulated to replace lost salts and sugars more effectively than plain water alone.
You should contact your healthcare provider immediately if you notice certain red flag symptoms that indicate a potential complication or severe dehydration. These include an inability to keep down even small sips of fluid for more than 12 to 24 hours, or not passing urine for eight hours or more. Reduced fetal movement is a separate and urgent reason to seek medical attention, as is the presence of a high fever or signs of preeclampsia, such as blurry vision.
Before calling your provider, gather specific information about your symptoms. Note the frequency and timing of any loose stools or vomiting. Also, note whether you are experiencing regular, tightening contractions, which helps them assess if labor is truly underway. Tracking fluid intake and output is useful for determining the severity of dehydration.